综合资讯 技术文章 原文阅读 在线商城 下载专区 DATASHEET 技术论坛 商务频道

电子技术 | 技术资料 | 嵌入式系统 | 单片机专题 | DSP专题
EDA/PLD专题 | 电源技术专题 | 电子制作专题 | 其他综合 | 芯片选型

所在的位置:首页在线阅读EDA/PLD专题VHDL程序举例-组合逻辑正文
 
双2-4译码器:74139

-- Dual 2-to-4 Decoder
-- A set of conditional signal assignments model a dual 2-to-4 decoder
-- uses 1993 std VHDL
-- download from: www.pld.com.cn & www.fpga.com.cn

library IEEE;
use IEEE.Std_logic_1164.all;


entity HCT139 is  
   port(A2, B2, G2BAR, A1, B1, G1BAR : in std_logic;
            Y20, Y21, Y22, Y23, Y10, Y11, Y12, Y13 : out std_logic);
end HCT139;

architecture VER1 of HCT139 is
begin
   Y10 <= '0' when (B1 = '0') and ((A1 = '0') and (G1BAR = '0')) else '1';  
   Y11 <= '0' when (B1 = '0') and ((A1 = '1') and (G1BAR = '0')) else '1';
   Y12 <= '0' when (B1 = '1') and ((A1 = '0') and (G1BAR = '0')) else '1';
   Y13 <= '0' when (B1 = '1') and ((A1 = '1') and (G1BAR = '0')) else '1';
   Y20 <= '0' when (B2 = '0') and ((A2 = '0') and (G2BAR = '0')) else '1';  
   Y21 <= '0' when (B2 = '0') and ((A2 = '1') and (G2BAR = '0')) else '1';
   Y22 <= '0' when (B2 = '1') and ((A2 = '0') and (G2BAR = '0')) else '1';
   Y23 <= '0' when (B2 = '1') and ((A2 = '1') and (G2BAR = '0')) else '1';
end VER1

返回 上一页 下一页   信息发布:工号01   转引自: 【 】 【打印】 【关闭

关于我们 ┋ 友情链接


深圳市福田区海滨广场福业大厦12C
电话:0755-88305880 25960580 传真:0755-88305880
Copyright©2005-2007 无忧电子开发网版权所有

粤ICP备05064233号